Industrial and municipal waters oftentimes contain a combination of volatile and nonvolatile organic contaminants. Treatment objectives for these waters vary depending on regulatory standards, treatment costs and the intended use of the water. For example, in drinking water applications and in some food and pharmaceutical process applications, the treatment objective usually requires removal of organic chemicals to nondetectable levels.
This invention relates to a process for the treatment of water, especially groundwater, which contains volatile and nonvolatile organic contaminants. This process can economically remove these organic contaminants to any desired concentration level, including nondetectable levels, and therefore constitutes a notable advance in the art of water treatment.
Two technologies are commonly used in the art for the treatment of groundwater. These include the use of packed tower air strippers and the use of activated carbon. Packed tower air strippers are effective in removing up to 99 percent of volatile organics from groundwater, but, due to size and energy contraints, generally cannot reduce the volatiles to nondetectable levels. Also, they cannot remove nonvolatile organics such as pesticides from groundwater and are subject to fouling, scale and/or biological growth.
Activated carbon alone can remove both volatile and nonvolatile organics, but a "nondetectable" treatment objective oftentimes requires a high carbon dosage, quite possibly making operating costs unacceptably high.
Accordingly, the need exists for a low cost method of reducing both volatile and nonvolatile organic contaminant levels in water, especially groundwater, streams to nondetectable levels, i.e. less than 1.0 ppb.
It is therefore an object of this invention to provide a process for the removal of volatile and nonvolatile organic chemicals from water, especially groundwater, preferably to nondetectable levels. Groundwater includes, but is not limited to, water which is contaminated by agricultural chemicals, such as pesticides, herbicides and fertilizers, chemical spills, septic tank leakage, storage tank leakage, landfill leachate and lagoon leachate.
It is a further object of this invention to provide a process for the removal of organics from groundwater which minimizes operator attention, maintenance and cost of removal.
It is still a further object of this invention to provide a process for the removal of organics from groundwater which eliminates the use of packed tower air strippers, and associated fouling due to scale and/or biological growth.
These and other objects of this invention are accomplished by a process in which contaminated water containing volatile and nonvolatile organic contaminants is passed through an induced draft air stripper followed by passing the effluent of said induced draft air stripper through a carbon adsorption bed, thereby removing said organic contaminants according to treatment objectives, which in many cases may require removal to nondetectable levels.